Unlike the assignment of char * variables, strings are copied by value and not by reference. The string assignment operator = copies the actual bytes of the string from the source operand up to and including the null byte to the variable on the left-hand side, which must be of type string. You can create a new string variable by assigning it an expression of type string.

For example, the D statement:

s = "hello";

would create a new variable s of type string and copy the six bytes of the string "hello" into it (five printable characters, plus the null byte). String assignment is analogous to the C library function strcpy(), with the exception that if the source string exceeds the limit of the storage of the destination string, the resulting string is automatically truncated by a null byte at this limit.

You can also assign to a string variable an expression of a type that is compatible with strings. In this case, the D compiler automatically promotes the source expression to the string type and performs a string assignment. The D compiler permits any expression of type char * or of type char[n], that is, a scalar array of char of any size, to be promoted to a string.